Changes in posterior corneal elevation after small incision lenticule extraction for different myopic diopters.

AIM: To study the changes and effect factors of posterior corneal surface after small incision lenticule extraction (SMILE) with different myopic diopters. METHODS: Ninety eyes of 90 patients who underwent SMILE were included in this retrospective study. Patients were allocated into three groups based on the preoperative spherical equivalent (SE): low myopia (SE≥-3.00 D), moderate myopia (-3.00 D>SE>-6.00 D) and high myopia (SE≤-6.00 D). Posterior corneal surfaces were measured by a Scheimpflug camera preoperatively and different postoperative times (1wk, 1, 3, 6mo, and 1y). Posterior mean elevation (PME) at 25 predetermined points of 3 concentric circles (2-, 4-, and 6-mm diameter) above the best fit sphere was analyzed. RESULTS: All surgeries were completed uneventfully and no ectasia was found through the observation. The difference of myopia group was significant at the 2-mm ring at 1 and 3mo postoperatively (1mo: P=0.017; 3mo: P=0.018). The effect of time on ΔPME was statistically significant (2-mm ring: P=0.001; 4-mm ring: P<0.001; 6-mm ring: P<0.001). The effect of different corneal locations on ΔPME was significant except 1wk postoperatively (1mo: P=0.000; 3mo: P=0.000; 6mo: P=0.001; 1y: P=0.001). Posterior corneal stability was linearly correlated with SE, central corneal thickness, ablation depth, residual bed thickness, percent ablation depth and percent stromal bed thickness. CONCLUSION: The posterior corneal surface changes dynamically after SMILE. No protrusion is observed on the posterior corneal surface in patients with different degrees of myopia within one year after surgery. SMILE has good stability, accuracy, safety and predictability.

Atonal homolog 7 (ATOH7) confers neuroprotection for photoreceptor cells in glaucoma via inhibition of the notch pathway.

Single-cell RNA sequencing (scRNA-seq) technologies enable the profiling and analysis of the transcriptomes of single cells and hold promise for clarifying gene mechanisms at single-cell resolution. We based this study on scRNA-seq data to reveal glaucoma-related genes and downstream pathways with neuroprotection effects. The scRNA-seq datasets related to glaucoma of retinal tissue samples of human beings and Atonal Homolog 7 (ATOH7)-null mice were obtained from the GEO database. The 74 top marker genes and 20 cell clusters were obtained in human retinal tissue samples. The key gene ATOH7 was found after the intersection with genes from GeneCards data. In the ATOH7-null mouse retinal tissue samples, pseudotime inference demonstrated significant changes in cell differentiation. Moreover, mouse retinal photoreceptor cells (PRCs) were cultured and treated with lentivirus carrying oe-ATOH7 alone or in combination with Notch signaling pathway activator Jagged-1/FC, after which cell biological functions were determined. The involvement of ATOH7 in glaucoma was identified through regulating PRCs. Furthermore, ATOH7 conferred neuroprotection in PRCs in glaucoma by mediating the Notch signaling pathway. In vitro data confirmed that ATOH7 overexpression promoted the differentiation of PRCs and inhibited their apoptosis by suppressing the Notch signaling pathway. The evidence provided by our study highlighted the involvement of ATOH7 in the blockade of the Notch signaling pathway, resulting in the neuroprotection for PRCs in glaucoma.

High-Throughput Sequencing Data Reveal an Antiangiogenic Role of HNF4A-Mediated CACNA1A/VEGFA Axis in Proliferative Diabetic Retinopathy.

Purpose: Proliferative diabetic retinopathy (PDR) is characterized by retinal new vessel formation, pointing to the importance of the antiangiogenic treatment in PDR. Hepatocyte nuclear factor 4A (HNF4A) has been highlighted to inhibit vascular endothelial growth factor (VEGF)-stimulated in vitro angiogenesis. Therefore, this study aims to elucidate the potential antiangiogenic mechanisms of HNF4A in PDR. Methods: PDR-related high-throughput sequencing datasets (GSE94019, GSE102485, and GSE191210) were obtained from the Gene Expression Omnibus (GEO) database, followed by the screening of differentially expressed genes (DEGs). The protein-protein interaction (PPI) network of the candidate DEGs was constructed based on gene set enrichment analysis (GSEA) data and Search Tool for the Retrieval of Interacting Genes (STRING) data. In addition, the key genes and pathways related to angiogenesis were screened by functional enrichment analysis. Furthermore, human retinal microvascular cells were used for further in vitro validation. Results: Four key genes (CACNA1A, CACNA1E, PDE1B, and CHRM3) related to PDR were identified in the grey module. CACNA1A affected angiogenesis in PDR by regulating vascular endothelial growth factor A (VEGFA) expression. Furthermore, HNF4A participated in angiogenesis in PDR by activating CACNA1A. In vitro experiments further identified that inhibition of HNF4A reduced CACNA1A expression and increased VEGFA expression, thus promoting angiogenesis in PDR. Conclusions: In conclusion, the obtained findings suggest that antiangiogenic HNF4A activates the CACNA1A/VEGFA axis in PDR. Our work provides new insights into the angiogenic mechanism of PDR and offers potential targets for translational applications.

Protective mechanism of TCF7L1 against retinal photoreceptor cell injury following retinitis pigmentosa based on the GEO database.

Recent studies have reported the promising value of differential gene expression analysis and weighted gene coexpression network analysis (WGCNA) for identifying disease biomarkers. Based on this method, this study intends to characterize the hub genes and pathways related to retinal photoreceptor cell (PRC) injury in the context of retinitis pigmentosa (RP). A total of 53 coexpression modules were identified by WGCNA, among which lightpink4, darkolivegreen, tan4, blue2, skyblue2, and navajowhite2 ranked at the top. By analyzing the RP microarrays retrieved from the GEO database, 338 differentially expressed genes (DEGs) were identified in the RP samples. Forty-five candidate genes were selected from these DEGs by intersection with the genes in the coexpression modules. These intersection genes were subjected to GO and KEGG analyses. Furthermore, the genes and pathways involved in PRC damage were identified based on analyses utilizing GeneCards and STRING tools. Transcription factor 7-like 1 (TCF7L1, also called TCF3) was suggested to participate in the RP-associated PRC damage through the Wnt signaling pathway. It was validated in a blue light-irradiated cell model that TCF7L1 overexpression boosted PRC viability and repressed apoptosis. Inhibition of the Wnt signaling pathway also contributed to protective effects. Together, the data mentioned above supported the conclusion that either elevation of TCF7L1 or blockade of the Wnt signaling pathway could prevent RP progression by protecting PRCs from damage.

An Update on Novel Ocular Nanosystems with Possible Benefits in the Treatment of Corneal Neovascularization.

Corneal neovascularization (CNV) is an ocular pathological change that results from an imbalance between angiogenic factors and antiangiogenic factors as a result of various ocular insults, including infection, inflammation, hypoxia, trauma, corneal degeneration, and corneal transplantation. Current clinical strategies for the treatment of CNV include pharmacological treatment and surgical intervention. Despite some degree of success, the current treatment strategies are restricted by limited efficacy, adverse effects, and a short duration of action. Recently, gene-based antiangiogenic therapy has become an emerging strategy that has attracted considerable interest. However, potential complications with the use of viral vectors, such as potential genotoxicity resulting from long-term expression and nonspecific targeting, cannot be ignored. The use of ocular nanosystems (ONS) based on nanotechnology has emerged as a great advantage in ocular disease treatment during the last two decades. The potential functions of ONS range from nanocarriers, which deliver drugs and genes to target sites in the eye, to therapeutic agents themselves. Various preclinical studies conducted to date have demonstrated promising results of the use of ONS in the treatment of CNV. In this review, we provide an overview of CNV and its current therapeutic strategies and summarize the properties and applications of various ONS related to the treatment of CNV reported to date. Our goal is to provide a comprehensive review of these considerable advances in ONS in the field of CNV therapy over the past two decades to fill the gaps in previous related reports. Finally, we discuss existing challenges and future perspectives of the use of ONS in CNV therapy, with the goal of providing a theoretical contribution to facilitate future practical growth in the area.

A ZFP42/MARK2 regulatory network reduces the damage of retinal ganglion cells in glaucoma: a study based on GEO dataset and in vitro experiments.

Glaucoma is a common disorder in which the death of retinal ganglion cells (RGCs) results in a progressive loss of sight, even blindness. This study was performed to reveal the key molecular mechanism of RGC damage in glaucoma based on the Gene Expression Omnibus database. Glaucoma-related microarray datasets were identified, followed by collection of differentially expressed genes (DEGs) with the key genes discovered by weighted gene co-expression network analysis. Through LASSO regression analysis, candidate genes involved in the pathogenesis of glaucoma were identified with their accuracy evaluated by receiver operating characteristic curve analysis. The glaucoma-specific transcriptional regulatory network was constructed to determine the key transcription factor regulatory axis. Then, in vitro cell models were established using H2O2 for further verifying the regulatory role of identified ZFP42/MARK2 axis in RGC damage in glaucoma. Differential analysis of GSE27276, GSE45570, and GSE101727 microarray datasets yielded 165 DEGs, and 22 key genes were identified following. Then, 9 candidate genes involved in the pathogenesis of glaucoma was collected and the key ZFP42/MARK2 regulatory axis was found. In vitro cell experiments further confirmed that ZFP42 and MARK2 were down-regulated in RGCs treated with H2O2. In addition, overexpression of ZFP42 increased the expression of MARK2 to increase RGC cell viability, and reduce cell apoptosis and ROS levels, while silencing MARK2 could reverse the protective effect of ZFP42. We confirmed that ZFP42 reduced the damage of RGCs in glaucoma by up-regulating the expression of MARK2.

The Roles of Various Prostaglandins in Fibrosis: A Review.

Organ fibrosis is a common pathological result of various chronic diseases with multiple causes. Fibrosis is characterized by the excessive deposition of extracellular matrix and eventually leads to the destruction of the tissue structure and impaired organ function. Prostaglandins are produced by arachidonic acid through cyclooxygenases and various prostaglandin-specific synthases. Prostaglandins bind to homologous receptors on adjacent tissue cells in an autocrine or paracrine manner and participate in the regulation of a series of physiological or pathological processes, including fibrosis. This review summarizes the properties, synthesis, and degradation of various prostaglandins, as well as the roles of these prostaglandins and their receptors in fibrosis in multiple models to reveal the clinical significance of prostaglandins and their receptors in the treatment of fibrosis.

5­Nitro­2­(3­phenylpropylamino) benzoic acid induces apoptosis of human lens epithelial cells via reactive oxygen species and endoplasmic reticulum stress through the mitochondrial apoptosis pathway.

Cataracts have a high incidence and prevalence rate worldwide, and they are the leading cause of blindness. Lens epithelial cell (LEC) apoptosis is often analysed in cataract research since it is the pathological basis of cataracts, except for congenital cataract. Chloride channels are present in ocular tissues, such as in trabecular cells, LECs and other cells. They serve an important role in apoptosis and participate in endoplasmic reticulum (ER) stress and oxidative stress. However, their role in the apoptosis of LECs has not been discussed. The present study examined the effects of the chloride channel blocker 5­nitro­2­(3­phenylpropylamino) benzoic acid (NPPB) in human LECs (HLECs) to elucidate the role of NPPB in HLECs and investigate the role and mechanism of chloride channels in cataract formation. HLECs were exposed to NPPB. Cell survival rate was evaluated using Cell Counting Kit­8 assays. Oxidative stress was detected as reactive oxygen species (ROS) in cells by using a ROS assay kit. Apoptosis was examined by assessing mitochondrial membrane potential and using a JC­1 assay kit, and western blot analysis was performed to measure the expression levels of mitochondrial­dependent apoptosis pathway­associated proteins. ER stress was evaluated by determining the intracellular calcium ion fluorescence intensity, and western blot analysis was performed to measure ER stress­associated protein expression. The results revealed that NPPB treatment decreased the viability of HLECs and increased apoptosis. Additionally, NPPB increased intracellular ROS levels, as well as the number of JC­1 monomers and the protein expression levels of B­cell lymphoma­2 (Bcl­2)­associated X and cleaved caspase­3, and decreased Bcl­2 protein expression. NPPB increased intracellular calcium ions, the protein expression levels of activating transcription factor 6, JNK, C/EBP homologous protein and caspase­12, and the phosphorylation of protein kinase R­like endoplasmic reticulum kinase. N­acetylcysteine and 4­phenylbutyric acid inhibited NPPB­induced oxidative stress, ER stress and apoptosis. Therefore, NPPB treatment decreased cell viability and promoted apoptosis of HLECs via the promotion of oxidative and ER stress.

An update: mechanisms of microRNA in primary open-angle glaucoma.

Glaucoma is a disease with characteristic optic neuropathy and loss of vision, leading to blindness, and primary open-angle glaucoma (POAG) is the most common glaucoma type throughout the world. Genetic susceptibility is the main factor in POAG, and most susceptibility genes cause changes in microRNA expression and function, thereby leading to POAG occurrence and development. Increasing evidence indicates that many microRNAs are involved in the regulation of intraocular pressure (IOP) and play an important role in the increase in IOP in POAG. Additionally, microRNA is closely related to optic nerve damage factors (mechanical stress, hypoxia and inflammation). This review discusses the effect of single-nucleotide polymorphisms in POAG-related genes on microRNA and the value of microRNA in the diagnosis and treatment of POAG.

microRNA-199a-5p regulates epithelial-to-mesenchymal transition in diabetic cataract by targeting SP1 gene.

BACKGROUND: As a common ocular complication of diabetes mellitus, diabetic cataract is becoming a leading cause of visual impairment. The progression of diabetic cataract progression involves epithelial-to-mesenchymal transition (EMT), the precise role of which remains to be investigated. As microRNAs (miRNAs) are suggested to be involved in the pathogenesis of many diseases, identification of aberrantly expressed miRNAs in diabetic lens epithelial cells (LECs) and their targets may provide insights into our understanding of diabetic cataract and potential therapeutic targets. METHODS: Diabetic cataract capsules and LECs exposed to high glucose (25 mmol/L, 1-5 days) were used to mimic the model. Quantitative RT-PCR was performed to evaluate the differential expression of miRNA. Dual luciferase reporter assay was used to identify the binding target of miR-199a-5p. The expression of EMT-associated proteins was determined by immunofluorescence and Western blot analysis. RESULTS: Our results showed the differential expression of miR-9, -16, -22, -199a and -204. MiR-199a was downregulated in diabetic cataract capsule and hyperglycemia-conditioned human LECs. Specific protein 1 could be directly targeted and regulated by miR-199a in LECs and inhibit EMT in diabetic LECs. CONCLUSION: Our findings implied miR-199a could be a therapeutic target by regulating SP1 directly to affect EMT in diabetic cataract and provided novel insights into the pathogenesis of diabetic cataract.

Development and clinical deployment of a smartphone-based visual field deep learning system for glaucoma detection.

By 2040, ~100 million people will have glaucoma. To date, there are a lack of high-efficiency glaucoma diagnostic tools based on visual fields (VFs). Herein, we develop and evaluate the performance of 'iGlaucoma', a smartphone application-based deep learning system (DLS) in detecting glaucomatous VF changes. A total of 1,614,808 data points of 10,784 VFs (5542 patients) from seven centers in China were included in this study, divided over two phases. In Phase I, 1,581,060 data points from 10,135 VFs of 5105 patients were included to train (8424 VFs), validate (598 VFs) and test (3 independent test sets-200, 406, 507 samples) the diagnostic performance of the DLS. In Phase II, using the same DLS, iGlaucoma cloud-based application further tested on 33,748 data points from 649 VFs of 437 patients from three glaucoma clinics. With reference to three experienced expert glaucomatologists, the diagnostic performance (area under curve [AUC], sensitivity and specificity) of the DLS and six ophthalmologists were evaluated in detecting glaucoma. In Phase I, the DLS outperformed all six ophthalmologists in the three test sets (AUC of 0.834-0.877, with a sensitivity of 0.831-0.922 and a specificity of 0.676-0.709). In Phase II, iGlaucoma had 0.99 accuracy in recognizing different patterns in pattern deviation probability plots region, with corresponding AUC, sensitivity and specificity of 0.966 (0.953-0.979), 0.954 (0.930-0.977), and 0.873 (0.838-0.908), respectively. The 'iGlaucoma' is a clinically effective glaucoma diagnostic tool to detect glaucoma from humphrey VFs, although the target population will need to be carefully identified with glaucoma expertise input.

Potential Protective and Therapeutic Roles of the Nrf2 Pathway in Ocular Diseases: An Update.

Nuclear factor- (erythroid-derived 2-) like 2 (Nrf2) is a regulator of many processes of life, and it plays an important role in antioxidant, anti-inflammatory, and antifibrotic responses and in cancer. This review is focused on the potential mechanism of Nrf2 in the occurrence and development of ocular diseases. Also, several Nrf2 inducers, including noncoding RNAs and exogenous compounds, which control the expression of Nrf2 through different pathways, are discussed in ocular disease models and ocular cells, protecting them from dysfunctional changes. Therefore, Nrf2 might be a potential target of protecting ocular cells from various stresses and preventing ocular diseases.

Fungal keratitis: Pathogenesis, diagnosis and prevention.

As a kind of serious, potentially sight-threatening corneal infections with poor prognosis, fungal keratitis can bring a heavy economic burden to patients and seriously affect the quality of life, especially those in developing countries where fungal keratitis is more prevalent. Typical clinical features include immune rings, satellite lesions, pseudopods, hypha moss, hypopyon and endothelial plaques. The ideal therapeutic effects could not be achieved by current treatments for many reasons. Therefore, under the current status, understanding the pathogenesis, early diagnosis and prevention strategies might be of great importance. Here, in this review, we discuss the recent progresses that may advance our understanding of pathogenesis, early diagnosis and prevention of fungal keratitis.